Heterostructured SnSe-MnSe@rGO as a composite electrode for Li-ion batteries and high energy density asymmetric supercapacitors

Systematically fabricated hybrid nanomaterials have good outer walls and inherent features, which can significantly improve energy storage capabilities. Herein, we demonstrated the successful preparation of heterostructure SnSe-MnSe nanomaterials anchored reduced Graphene oxide using the hydrothermal method. The SnSe-MnSe@rGO is used as the composite electrode for lithium-ion battery and supercapacitor applications. The SnSe, MnSe, and SnSe-MnSe materials were also prepared and compared their performances with the SnSe-MnSe@rGO material. The first cycle charge/discharge capacity of SnSe-MnSe@rGO was 484.6/641.9 mAhg−1 at 0.1Ag−1 with coulombic efficiency of 75.49 %. After 1000 cycles at 1Ag−1, the SnSe-MnSe@rGO delivered the discharge capacity of 175.7 mAhg−1 at 1Ag−1 with 72.75 % retention of capacity. For supercapacitor application, the SnSe-MnSe@rGO exhibits the battery-type energy storage mechanism and provides a specific capacity of 210. 8 mAhg−1 at 1 Ag−1 with superior rate capability and it withstands 94 % of initial capacity after 5000 GCD cycles at 20 Ag−1 in three-electrode electrochemical cells. The asymmetric type such as activated carbon//SnSe-MnSe@rGO device delivers the capacity of 105.8 mAhg−1 and shows a high energy density of 84.7 Whkg−1 with the power density of 810.5 Wkg−1 at 1 Ag−1. The device holds 89 % of its initial capacity retention after 10,000 continuous GCD cycles at 10 Ag−1. This study emphasizes a comprehensive and fundamental understanding of the reaction mechanisms at the heterostructures, as well as the strategic design of composite materials for constructing advanced electrodes in the realm of sustainable energy storage applications.